There is a new version (v47) with a few extra checks before trying to click the ‘Let’s go’ button.
This is an attempt to handle situations where the final click on ‘Let’s go’ doesn’t happen.
Tip: You can also try setting the ‘Wait longer for Launcher window’ option (or use the /extrawait command line switch) to make zwift-login wait a bit longer for changes in the launcher window.